Injury or disease may require surgery to immobilize a spinal segment. Conventional immobilization techniques require screw fixation of rods or plates to pedicles.
Known techniques include pedicle screw insertion steps for probing, drilling, inserting X-ray markers, imaging and tapping. For example, pursuant to one common surgical technique:
(1) optimum location of the pedicle screw is determined by inserting a probe into a pilot hole in the pedicle, PA1 (2) the pilot hole is reamed with a front cutting bit to form a pedicle screw anchor hole, PA1 (3) an X-ray marker is inserted into the anchor hole, and X-rays are taken to assure that the anchor hole is properly positioned, formed, and of an appropriate depth to accommodate the required pedicle screw length, PA1 (4) the anchor hole is tapped by providing threads in its sidewall, and PA1 (5) a pedicle screw is screwed into the tapped anchor hole.
Such techniques are attended by a plurality of disadvantages including significant risk of nerve root injury.